Wave motions in a collapsible tube conveying fluid.

This paper presents a refinement of the authors' previous analysis and additional numerical results. In order to study self-excited oscillation of a finite-length collapsible tube, a simple two-dimensional channel model analysis has been proposed using an existing one-dimensional flow theory which may account for the pressure loss due to flow separation. A flexible part of the channel consists of two elastic membranes supported by distributed nonlinear springs from the outsides. The analysis includes the effect of longitudinal membrane tensions caused by an initial stretching and membrane deflection. According to numerical analyses, an initially stretched membrane channel may have a wide region of the flow separation at the downstream of the channel throat located in the neighborhood of the middle point of the channel. The induced oscillations become large and chaotic. Some details of wave motions of membrane deflection, flow velocity and pressure are given.